1. Field of the Invention
The present invention relates to an ink tank for a liquid jet recording apparatus that records by discharging ink. More particularly, the invention relates to an ink tank having a plurality of joint portions with respect to the ink jet printing system that consumes a large amount of ink.
2. Related Background Art
An ink tank (a liquid container) used for an ink jet recording apparatus is structured to be detachably mountable on an ink tank unit, which is an ink tank installing portion of the recording apparatus, in order to make it easier to exchange ink tanks when ink is consumed. For the ink tank, the ink supply port is arranged with a rubber plug or the like for the prevention of ink leakage when dealing with the ink tank as an individual body at the time of deliver or exchange thereof. At the same time, a hollow needle or the like is arranged for the ink tank unit for use of the connection with the ink tank, which makes the ink supply possible from the ink tank when it is connected with the ink supply port of the ink tank.
For the inner structure of the ink tank, there have been known various modes, such as the one that retains ink in the sponge or the some others material that generate capillary force, the one that retains ink in a flexible bag, or the one that retains ink directly in a rigid housing. Particularly, for the recording apparatus arranged to make a steady ink supply by keeping the water head difference constant between the head and the liquid surface of the tank by use of tubes or the like to connect the recording head and the ink tank, it is preferable to adopt the structure arranged to contain ink directly in the tank housing also from the viewpoint that this structure makes the reduction of part numbers possible.
The ink tank that adopts the aforesaid structure is provided with the communication port with the air outside for releasing the interior of the housing to the atmosphere when supplying ink. This communication port with the air outside is also sealed with closing means, such as a rubber plug, in order to prevent the ink leakage or the like when the ink tank is handled as an individual body. This closing means is arranged to be released when the ink tank is installed on the ink tank unit side.
However, for a larger type ink jet recording apparatus that consumes a large amount of ink due to the higher printing duty, a large capacity ink tank, such as 500 cc or more, is often used so as to suppress the frequency of the ink tank exchanges. Here, however, in order to adopt the aforesaid structure for such a large capacity ink tank as described above, it is required to manufacture the container itself in higher precision for the implementation of the reliable connection if the positioning section of the installation to the tank unit should be located away from the jointing portion, such as ink supply port or the communication port with the air outside. Here, a larger hollow container, which is capable of storing liquid directly in the interior thereof, is usually made with plastic by the blowing formation so as to provide the container at lower costs. Therefore, it is difficult to improve the dimensional precision of the container while maintaining the lower costs as usual.
Further, in recent years, it has been required to use plural kinds of ink having different densities or colorants for the implementation of the highly precise recording in higher image quality by use of the aforesaid apparatus. As a result, it is also required for the tank itself to be provided with a mechanism to prevent erroneous installation so that there is no possibility that a wrong ink tank is installed on the tank unit. As to such mechanism to prevent the erroneous installation, too, a higher precision is required, as the kinds of ink tanks, which should be installed on one tank unit, are increased. Then, for the recording apparatus for use of medical equipment, for use of the CAD outputs, for use of poster outputs, or for use of some other special purposes, it is required to make the precision higher still eventually for the mechanism on the tank side to prevent the erroneous installation if the tank unit should be arranged to be shareably usable by each of the apparatuses for the implementation of the lower-cost manufacture thereof, because the kinds of tanks that should be discriminated from one another become many inevitably in this case.
Of the two subjects discussed above, some of the inventors hereof have already filed the patent application as to the coupling method of an ink tank and an ink tank with a view to solving the problems encountered in making the ink tank larger. In this respect, the inventors hereof have further studied the subjects as a whole. On the basis of the new findings after such studies, the invention here of is designed.
It is an object of the invention to provide a highly reliable large ink tank capable of storing liquid directly in it with a comparatively simple structure with a smaller amount of variations of dimensional precision per product at lower costs by dealing with the two subjects related to the installation and coupling with the tank unit at a time. It is also the object of the invention to provide a method for manufacturing such ink tank.
In order to achieve the objects described above, the ink tank of the present invention comprises a housing detachably mountable on a liquid jet recording apparatus, which is capable of retaining liquid directly in the interior thereof; a supply portion for supplying liquid retained in the housing to the recording apparatus; and a communication portion with the air outside for communicating the interior of the housing with the air outside. For this ink tank, the supply portion and the communication portion with the air outside are integrally formed, and at the same time, a plate member is provided to make the interior of the housing a closed space by joining the plate member to the housing, and then, erroneous installation prevention portions are arranged for the plate member to prevent the installation on the position other than specifically designated for the liquid jet recording apparatus.
Also, the method of the present invention for manufacturing an ink tank, which is provided with a housing detachably mountable on a liquid jet recording apparatus, at the same time, being capable of retaining liquid directly in the interior thereof; a supply portion for supplying liquid retained in the housing to the recording apparatus; and a communication portion with the air outside for communicating the interior of the housing with the air outside, comprises the steps of preparing a plate member provided with the supply portion and the communication portion with the air outside on the same surface, at the same time, being provided with erroneous installation prevention portions for preventing the installation on the position other than specifically designated for the liquid jet recording apparatus, the plate member being joined to the housing for making the interior of the housing a closed space; positioning the plate member with respect to the housing; welding the plate member to the housing. For this method of manufacture, the plate member is positioned in two directions orthogonal to the joining direction of the liquid jet recording apparatus, at the same time intersecting each other with respect to the housing in the step of positioning.
Also, the method of the present invention for manufacturing an ink tank, which is provided with a housing detachably mountable on a liquid jet recording apparatus, at the same time, being capable of retaining liquid directly in the interior thereof; a supply portion for supplying liquid retained in the housing to the recording apparatus; and a communication portion with the air outside for communicating the interior of the housing with the air outside, comprises the steps of preparing an ink tank provided with a plate member provided integrally with erroneous installation prevention portions for preventing the installation on the position other than specifically designated for the liquid jet recording apparatus, the supply portion, and the communication portion with the air outside, at the same time, making the interior of the housing a closed space by being joined to the housing; and injecting ink through either one of the communication portion with the air outside and the supply portion of the ink tank, at the same time, exhausting the air in the interior of the housing from the other portion to the outside of the housing.
In accordance with the ink tank and the method for manufacturing the ink tank described above, it becomes possible to easily enhance the dimensional precision of the coupling portion with the recording apparatus, as well as that of the erroneous installation prevention portions. Therefore, without depending on the precision of an ink tank as a whole, it is possible to enhance the reliability of the installation on or coupling with the recording apparatus.